Contaminants such as CO2, H2S and O2 in liquid and gas pipelines in the presence of water create an aggressive environment conducive to internal corrosion. During pipeline operations, solids deposition, water accumulation, bacterial activities and improper chemical inhibition aggravate the internal corrosion attack. For assessing the threat of internal corrosion the industry has only three integrity validation tools at its disposal. These are Pressure Testing, In Line Inspection (ILI) and Internal Corrosion Direct Assessment (ICDA). To enhance pipeline integrity for piggable and non-piggable pipelines, NACE International published a variety of Standard Practices for the ICDA protocols for predicting time-dependent internal corrosion threats for various products in both offshore and onshore in sweet or sour service.
All ICDA protocols are a structured, iterative integrity assessment process, consisting of the following four steps: Pre-assessment, Indirect Inspection, Detailed Examination and Post-assessment. Most importantly, unlike ILI and pressure testing, all ICDA standards require a mandatory root cause analysis and a go forward mitigation plan to arrest the corrosion processes being encountered.
This paper reviews one case study; LP-ICDA for three (3) “piggable” refined product pipelines from the Jetty to the onshore marketing terminal. This paper will be useful for the pipeline operators to provide guidance on not only identifying the locations at which internal corrosion activity has occurred but also look into how the operators used the ICDA program to better manage their asset.